NISAR

Why is in news? NASA hands over NISAR satellite to ISRO

NASA-ISRO Synthetic Aperture Radar (NISAR) is a Low Earth Orbit (LEO) observatory being jointly developed by NASA and ISRO.

NISAR has been built by space agencies of the US and India under a partnership agreement signed in 2014.

The NISAR is 2,800 kilograms satellite, will be the first radar of its kind in space to systematically map Earth, using two different radar frequencies (L-band and S-band) to measure changes in our planet's surface less than a centimeter across.

NISAR will map the entire globe in 12 days.

It provide spatially and temporally consistent data for understanding changes in Earth’s ecosystems, ice mass, vegetation biomass, sea level rise, ground water and natural hazards including earthquakes, tsunamis, volcanoes and landslides.

NISAR carries L and S dual band Synthetic Aperture Radar (SAR), which operates with Sweep SAR technique to achieve large swath with high resolution data.

By using synthetic aperture radar (SAR), NISAR will produce high-resolution images.

SAR is capable of penetrating clouds and can collect data day and night regardless of the weather conditions.

This flagship partnership would have major contributions from both agencies.

NASA is responsible for providing the L-Band SAR payload system and the GPS System in which the ISRO supplied S-Band SAR payload and both these SAR systems will make use of a large size (about 12m diameter) common unfurl able reflector antenna.

The NISAR Observatory will be launched from Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota on the southeast coast of the Indian peninsula, on the GSLV expendable launch vehicle contributed by ISRO by 2024.

The satellite will operate for a minimum of three years.

NASA requires the L-band radar for its global science operations for at least three years. Meanwhile, ISRO will utilise the S-band radar for a minimum of five years.

According to NASA, another important component of the satellite is its large 39-foot stationary antenna reflector. Made of a gold-plated wire mesh, the reflector will be used to focus “the radar signals emitted and received by the upward-facing feed on the instrument structure”.

ISRO will use NISAR for a variety of purposes including agricultural mapping, and monitoring of glaciers in the Himalayas, landslide-prone areas and changes in the coastline.